Seal for electrochromic devices

Abstract

An improved seal member is provided as a part of an electrochromic device to bond two glass elements together in a spaced-apart relationship. In one embodiment the seal member provides improved adhesion to a reflector/electrode on the third surface of an electrochromic mirror, or to a layer of metal on the second or third surface for an electrochromic light filter. This seal member comprises a mixture of an organic resin scaling system and an adhesion promoter, where the adhesion promotor comprises a first and a second region, where the first region interacts with the reflector/electrode or the metal layer, and a second region that interacts with the organic resin sealing system, and may even chemically react with the organic resin sealing system. In another embodiment the seal member is provided with a coefficient of thermal expansion that is closer to glass than a standard epoxy sealing system.

What is claimed is:  
     
       1. An electrochromic device, comprising front and rear spaced elements, each having front and rear surfaces, said rear surface of said front element having a layer of transparent conductive material disposed thereon, said front surface of said rear element having a layer of metal disposed thereon, said device further comprising a seal member bonding said front and rear spaced elements together in a spaced-apart relationship to define a chamber containing an electrochromic medium, said seal member comprising a sealing system and glass beads having an average diameter that is less than ⅔ of the dimension that said front and rear elements are spaced apart. 
     
     
       2. The electrochromic device of claim  1 , where said glass beads are present in an amount sufficient to lower the coefficient of thermal expansion of said seal member, while allowing said seal member, in its uncured state, to be easily dispensed or screen printed. 
     
     
       3. The electrochrornic device of claim  2 , where said amount is greater than about 40 percent by weight of said seal member. 
     
     
       4. The electrochromic device of claim  2 , where said glass bead dimension is less than ½ the dimension that said front and rear elements are spaced apart and greater than about 0.5 microns. 
     
     
       5. The electrochromic device of claim  2 , where said glass bead dimension is less than about 50 microns. 
     
     
       6. An electrochromic device, comprising front and rear spaced elements, each having front and rear surfaces, said rear surface of said front element having a layer of transparent conductive material disposed thereon, said front surface of said rear element having a layer of metal disposed thereon, said device further comprising a seal member bonding said front and rear spaced elements together in a spaced-apart relationship to define a chamber containing an electrochromic medium, said seal member comprising a sealing system and an inorganic filler, where the amount of said filler is greater than about 40 weight percent of said seal member. 
     
     
       7. The electrochromic device of claim  6 , where said inorganic filler has a negative coefficient of thermal expansion. 
     
     
       8. The electrochromic device of claim  7 , where said glass bead dimension is less than ½ the dimension that said front and rear elements are spaced apart and greater than about 0.5 microns. 
     
     
       9. The electrochromic device of claim  7 , where said glass bead dimension is less than about 50 microns. 
     
     
       10. The electrochromic device of claim  6 , where said amount is greater than about 40 percent by weight of said seal member. 
     
     
       11. The electrochromic device of claim  10 , where said amount is greater than about 60 percent by weight of said seal member. 
     
     
       12. An electrochromic device, comprising front and rear spaced elements, each having front and rear surfaces, said rear surface of said front element having a layer of transparent conductive material disposed thereon, said front surface of said rear element having a layer of metal disposed thereon, said device further comprising a seal member bonding said front and rear spaced elements together in a spaced-apart relationship to define a chamber containing an electrochromic medium, said seal member comprising a sealing system and an inorganic filler, where said inorganic filler has a negative coefficient of thermal expansion. 
     
     
       13. The electrochromic device of claim  12 , where said amount is greater than about 40 percent by weight of said seal member. 
     
     
       14. The electrochromic device of claim  13 , where said amount is greater than about 60 percent by weight of said seal member. 
     
     
       15. The electrochromic device of claim  12 , where said inorganic filler is beads and where the average dimension of said beads is less than ⅔ of the dimension that said front and rear spaced elements are spaced apart. 
     
     
       16. The electrochromic device of claim  15 , where said bead dimension is less than ½ the dimension that said front and rear elements are spaced apart and greater than about 0.5 microns. 
     
     
       17. The electrochromic mirror of claim  16 , where said bead dimension is less than 20 microns. 
     
     
       18. An electrochromic device, comprising front and rear spaced elements, each having front and rear surfaces and a seal member bonding said front and rear spaced elements together in a spaced-apart relationship to define a chamber that contains an electrochromic medium, where said device has means for applying a potential to said electrochromic medium, and where said seal member comprises inorganic filler beads having an average diameter that is less than ⅔ of the dimension that said front and rear elements are spaced apart. 
     
     
       19. The clectrochromic device of claim  18 , further including inorganic filler beads having an average diameter that is less than ½ the dimension that said front and rear elements are spaced apart. 
     
     
       20. The electrochromic device of claim  19 , further including inorganic filler beads having an average diameter that is less than about 50 microns. 
     
     
       21. The electrochromic device of claim  18 , further including inorganic filler beads having an average diameter that is less than about 50 microns. 
     
     
       22. An electrochromic device, comprising front and rear spaced elements, each having front and rear surfaces, and a seal member bonding said front and rear spaced elements together in a spaced-apart relationship to define a chamber that contains an electrochromic medium, where said device has means for applying a potential to said electrochromic medium, and where said seal member comprises an inorganic filler, where the amount of said filler is greater than about 40 weight percent of said seal member. 
     
     
       23. The electrochromic device of claim  22 , where said inorganic filler has a low or negative coefficient of thermal expansion.